CMOS photodetector with a wide working range

摘要

A CMOS charge-integration mode photo-detector built on an n-type substrate is disclosed in this invention. This photo-detector includes a p+n photodiode with the n-type substrate constituting an n-region and a p+ diffusion region disposed near a top surface of the n-type substrate, the p+ diffusion region constituting a charge integration node. The photo-detector further includes a gate-biased charge storable n-type MOS transistor functioning as a photo-conversion voltage amplifier supported on the substrate formed with a threshold voltage of Vt0 having a gate terminal connected to the charge integration node. The photo-detector further includes a MOS transistor supported on the substrate functioning as a readout switch transistor having a source terminal connected to a drain terminal of the gate-based charge storable n-type MOS transistor. The photo-detector further includes a pre-charge switch transistor supported on the substrate having a source terminal connected to the charge integration node and a drain terminal connected to a bias voltage source. In an alternate preferred embodiment, the photo-detector is formed in a p-type substrate.